feat: add toggleterm, markdown preview keymaps, lualine switch filename and navic (#23)

- Configured toggleterm plugin
- Added keymap for markdown preview
- Changed lualine so Navic is better readable by switching filename and
type with Navic.

config/plugins/ui/lualine.nix

@@ -46,6 +46,11 @@ _: {
             };
           };
         }
+        {
+          name = "navic";
+        }
+      ];
+      lualine_x = [
         {
           name = "filetype";
           extraConfig = {
@@ -63,11 +68,6 @@ _: {
             path = 1;
           };
         }
-      ];
-      lualine_x = [
-        {
-          name = "navic";
-        }
         {
           name.__raw = ''
             function()